I think it's a bit early to start guessing the spec sheet(s) of the coming new model(s) but still, if they really are to come up with a dSLR-format camera with a z-axis sensor and a hybrid mount fully compatible with all those three lens types, the body is likely to be a large-ish one. I'd think adding a 5-axis IBIS into that would be quite challenging, too.
But why speculate, when we know so little about the real thing(s), for now, and there's NAB, there's Photokina, etc.
Patience, young Luke, patience. :P
I tend to agree about the stills side in general, and the notion that stills and video shooting are two different crafts and forms of expression to begin with.
Nevertheless, think about all the millenials and the new breed of "geekier" shooters who have grown up, or learned the craft with all digital cameras and spray and pray shooting style. In fact, there are already quite a few people who share that sort of thinking, and therefore the notion of extracting stills from video frames may become the new norm, like it or not. I don't think it will totally replace traditional stills shooting any time soon, though. In fact, a change like that may again first start from the consumer side of things, rather than the pro/prosumer side.
The (kind of) camera(s) Sony apparently are up to aren't really intended for stills shooting to begin with, despite Andrew's personal views, so don't worry. Horses for courses. Sony will carry on making stills cameras next year, too, and most of this is rather premature, anyway. Speculating for the heck of it.
Nothing wrong with that, of course, but don't let mere speculation upset your piece of mind. ;)